1. Field of the Invention
The present invention relates to a spindle motor.
2. Description of the Related Art
In general, a fixed shaft-type spindle motor in which a shaft having high impact resistance is fixed to a case of a hard disk driving device is generally mounted in an information recording and reproducing device such as a hard disk driving device for a server.
That is, the shaft is fixedly installed in the spindle motor mounted in the hard disk driving device for a server in order to prevent a hard disk mounted thereon from being damaged and thereby stopping information from being recorded thereon or read therefrom, due to an external impact.
In addition, since it is demanded that a spindle motor used for an enterprise hard disk driving device have a high degree of reliability, it is necessary to manage an amount of a lubricating fluid provided in a fluid dynamic bearing assembly including a fixed-type shaft.
Meanwhile, in the case in which lubricating fluid is provided in the fluid dynamic bearing assembly, generally, the lubricating fluid is provided in a space formed between a sleeve and a lower thrust member.
However, a end portion of the lower thrust member and a surface of the sleeve opposed thereto, between which the lubricating fluid is provided and flows, are formed to have a predetermined angle, such that a phenomenon of condensation of the lubricating fluid may be generated in a space formed between the end portion of the lower thrust member and the surface of the sleeve opposed thereto.
That is, in the case in which the lubricating fluid is injected into the space formed between the end portion of the lower thrust member and the surface of the sleeve opposed thereto, the lubricating fluid may not be further introduced by a capillary phenomenon and a flow of the injected lubricating fluid may be hindered.
Therefore, a process of injecting the lubricating fluid may not be smoothly performed, such that a manufacturing yield may be reduced.